Bulk materials transport containers such as dump bodies on dump trucks, buckets on front end loaders and the like are used in many industries for the transport of materials from one area to another. For example, in the mining industry dump trucks are used to transport mined materials from the mine site to a processing site. In the case of the mining industry, as well as many other industries, the material transported can have a hardness that is greater than the material from which the container is formed, which is typically steel. As a result, the load materials can be very abrasive and movement of the materials across internal surfaces of the container during loading, and more particularly unloading, tends to wear the surfaces rapidly. Because of this the transport containers can experience significant down time whilst the surfaces are being refabricated to prolong the life of the container.
Movement of the materials across internal surfaces of the transport container, such as when the container is tipped to allow flow out of an end of the container, leads to abrasion or scoring of the metal of the container. Abrasion of the surface then results in an increased resistance to flow of material across the surface and therefore a resultant increase in difficulty in emptying the container.
In practice, it is known that once an area of the container has become abraded there can be a significant ‘hang up’ of material in the abraded area, which means that, despite the container being tilted or tipped to enable emptying of the material by gravity flow, some material does not flow out of the container under the influence of gravity alone. For example, referring to a dump body on the back of a dump truck, it has been known for the forward most area of the container adjacent the junction between the forward wall and floor of the container to become abraded so that when the container is tilted and the forward most area of the container is raised, the material can be hung up in that area and will not flow out of the container under the influence of gravity alone. Under these circumstances operators will normally rapidly raise and lower the dump body about its pivot in an attempt to jar the material loose. This procedure then leads to an accelerated wearing of the dump bodies as well as the hydraulic mechanism used to raise the dump body. Alternatively, some physical intervention is usually required to move the load out of the container, which then raises issues of additional time and danger in emptying the container.
To overcome these difficulties it is known to hang lines of heavy metal chains across the dump body so that as the body is emptied, the chains bang against the body and/or the material being emptied to thereby physically prevent material being hung up in the body.
In many materials transport containers it is known to provide wear plates on surfaces that are subject to constant abrasion. For example U.S. Pat. No. 6,076,693 to Reiter et al. describes a sacrificial one piece insert for a transport container such as a dump truck body. The liner is formed from a plastics material and can be interchanged when worn. Whilst the plastics liners may be useful for soft material such as flour, the hardness of material transported in the mining industry for example means that the liners wear rapidly and for that reason are not suited to many industries.
U.S. Pat. No. 6,007,132 to Burg et al. describes a liner suitable for use in the dump body of a dump truck. The liner has raised strips of an abrasion resistant cladding wherein the raised strips are aligned transverse to the flow of material so that the strips cause material to tumble rather than slide over the surface. This tumbling action is said to be less abrasive than a sliding action over the surface. However the raised strips protrude into the flow path of material and therefore are subjected to strong abrasive forces and therefore tend to wear faster than if the material was sliding over the surface.
U.S. Pat. No. 6,022,068 to D'Amico relates to a modified dump truck body with enhanced hardness and thickness toward the rear of the body. D'Amico also does not disclose the use of removable wear plates or the provision of an arcuate surface to assist in unloading.
U.S. Pat. No 6,174,014 to Hook et al., discloses the use of a liner for use in the rear of a dump truck body. The liner however is a web of protrusions and does not disclose a smooth surface, nor the provision of an arcuate surface between the floor and side or front walls of the dump truck.
In many instances the prior art addresses issues of minimising wear, but not of maximising the flow of material over a surface, and in particular over the surface of a dump body of a dump truck.